1. Students will be able to discuss the different waste management options and explain how each related to saving energy and resources.
2. Students will be able to explain why it is important to recycle paper and to purchase materials that use recycled paper.
3. Students will prepare their own recipes for recycled paper and will design a test for determining the strength of recycled paper.
4. Students will design experiments to discover the degradable nature of some packing materials and will explain the advantages of these materials over nonbiodegradable packing materials.
The science portion of this interdisciplinary unit focuses on helping students to understand the importance of reducing solid waste. In Activity 1, "Waste Not, Want Not", students are introduced to different solid waste management strategies including recycling, reusing, composting, reduction and landfilling. Students are encouraged to make choices that will help them to decrease the amount of material they send to the landfill each day. Activities 2 and 3 center around recycling paper. Students examine different types of paper to get a close look at fibers. They also design their own mechanism for testing paper strength. Finally, students make their own recycled paper. They develop their own secret recipe for paper as part of the activity and make designer recycled paper. In Activity 4, "Eco-Nuts", students learn the advantages, in terms of energy and resources, of using degradable packing materials rather than Styrofoam.
Students may not realize it, but a lot of energy is "thrown away" each day. When we put out the trash each week we are not only throwing away energy, but resources as well. Unless materials are recycled, the energy used to collect the raw material, the energy in the raw material itself, and the energy needed to transform the raw material into the objects we buy is landfilled. All of the energy used in the production and transportation of the items we buy cannot be regained. By reusing, recycling, and composting some of the energy and resources tied up in the object can be reused. By buying less (reducing) of a particular item we can use less resources and energy too.
The science portion of this module is concentrated on solid waste. How can we reduce the amount of material placed into the landfill each day? A good way to get students to be thinking in the reducing our "solid waste mode" is to hold a class discussion about solid waste. Activity 1 provides suggestions for a class discussion on solid waste.
If the math teacher in your team will not be teaching the mathematics portion of this module, you may wish to get ideas for opening discussion from the math section. The math activities comprising module 4 would be appropriate for science as well. Of course the ideal situation would be for the math portion of this module to be carried out in math class simultaneously with the science portion of the module.
Teacher Notes
Objectives:
Students will be able to discuss the different waste management options and explain how each relates to saving energy and resources.
Materials:
Solid Waste Management Option Cards:
Prepare the cards (one set per student group) by placing one of the following words on colored index cards, one word per card.
Reuse, Recycle, Landfill, Reduction, Composting
Waste Cards:
Prepare 1 set of cards for each student group. Using white index cards, place one of the following terms on each card.
milk jugs
cereal boxes
juice drink boxes
Styrofoam cups
pop cans
apple peels
grass clippings
glass jars
banana peels
foam packaging
coffee grounds
magazines
watermelon rinds
old dry cells
old paperback books
old toys
wood scraps
fireplace ashes
used motor oil
soup cans
yard leaves
old appliances that still work
orange peels
clothing that no longer fits
dirty disposable diapers
Styrofoam paint brushes
Background:
Every day we throw out everything from toothpaste tubes to old washing machines, from grass clippings to milk jugs, from newspapers and magazines to soup cans.
These materials are all solid waste. For our purposes we will classify solid waste as the materials we throw away in the trash can. Most of the solid waste we generate ends up in a landfill. A landfill is a place where waste is dumped, compacted, and covered with dirt. There are many options available for reducing the amount of waste which is landfilled. This activity will help illustrate
these options to students. The categories of waste management include reusing, recycling, reducing use, composting and finally landfilling the items we no longer want. A more detailed explanation of each category is provided in the
Suggested Teaching Strategies section.
Styrofoam is special case that warrants class discussion. Styrofoam is a kind of plastic made from oil. It took billions of years for the oil to form. This means we are using up some of our natural treasures when we use Styrofoam. It also adds more garbage to our world because Styrofoam is permanent garbage. It will not break down in a landfill. Five hundred years from now a girl may dig up a piece of a Styrofoam cup you drank from on a picnic. The best thing we can do is to avoid Styrofoam...simply don't buy it. If you eat at a fast food restaurant, ask for paper cups and plates instead of Styrofoam. Explain to the restaurant manager why you don't want to use Styrofoam. Try to avoid Styrofoam products like picnic plates, cups and even egg cartons. If the grocery store carries only Styrofoam egg cartons, ask the manager if they can switch to cardboard. Write a letter to the head of the company. Just think, a simple request like this could have a huge impact if the store decided to take your advice!
Suggested Teaching Strategies:
Before beginning this activity, it is important for students to know the meaning of the terms solid waste and landfill. Until students gain an appreciation for
the tremendous waste involved in burying the items we no longer want by throwing them away, they will not see the need to change their behavior. Many individuals believe that recycling is the only thing that can be done to reduce what we throw away. Recycling is a great beginning, but much more can be done
to reduce the amount of material we throw away.
Begin this activity by asking students to brainstorm a list of some of the items they typically throw away at their home. Place the list on the chalkboard. Once students have generated a fairly extensive list, ask them where this garbage goes once it is placed on the curb on trash day. Some students are bound to know that the garbage is landfilled. Take this opportunity to explain the terms solid waste and landfill to students (or better yet, get students to explain it to you).
Ask students to list ways we can reduce the amount of garbage thrown away each day. Most students will say "recycle", but that may be their only idea. Take this opportunity to explain the waste management options to students. Before simply giving them the information, provide students a chance to generate their own definitions by sharing their ideas during a class discussion. Broad definitions and examples for each solid waste option are provided below.
Procedure:
For this particular activity, no "student worksheet" is available. It is important that much of the important information required to complete the exercises outlined below should be gained by carefully guided class discussion.
Part 1: What's Happening Now
Place students into think pairs. Give each group of students a set of waste cards and a set of waste management cards. Students should spread the waste management cards (colored index cards) across the top of their desk. Ask
students to carefully consider the items written on each of the waste cards. Place each waste card (white) under the appropriate waste management card that illustrates how your family currently disposes of the item. Once you have arranged all of the cards, record your arrangement in a data table. Be sure to rearrange the cards to reflect the practices of each member of your group. It
is likely that each family will be handling their solid waste differently. Point out to students that they will have a chance later to rearrange their cards to show what they think they should be doing. Right now, we just want a
picture of what is currently being done. It is OK if some columns have no items listed. Once students have completed their arrangement, ask them to record their arrangement on a data table.
Student answers will vary greatly. Some students may have all items listed under the landfill category. It is important that these students not be made to feel badly because they do not recycle. Some students may be very sensitive on this issue.
Part 2: What Else Can We Do?
Ask students to prepare a second data table, using the same column headings as before. This time, as a group, rearrange the cards to show how best to dispose
of each of the items listed on the waste cards. By "best" we mean how can the use of energy and natural resources be minimized. There is no "right" or "wrong" combination for Data Table 2.
The categorization shown in Data Table 2 will likely vary with each student group and this is O.K. Use the differences as a point of discussion. Ask students to explain their placement of items in Data Table 2. Are there any items their family would be willing to no longer purchase?
Summing Up:
1. Arrange the five waste management categories into a diagram form which illustrates which management approach or approaches are the "best" in terms of
energy and resource savings and which are the "worst". Write several sentences explaining your reasons for arranging the management strategies as you did.
2. Prepare a "Paper Recycling Tips" sheet to take to your home. Share the completed tips with your parents. (A sample tip sheet is provided in Appendix A. page 68. It would be much better not to show this to students, but to have them develop their own tip sheet.)
Home/Community Connection:
Reuse It: If you are really interested in decreasing your solid waste, saving energy and resources, and helping others, start by focusing on reuse. With your parents permission, look through your room, attic, basement and
garage. Find those things you no longer need or want, but which someone else may want. Before donating the items, check with your parents to make sure it is OK. While you are at it, get your parents to clean out their things as well.
Take the items to an appropriate agency or organize and hold your own garage sale. Be sure to give the garage sale leftovers away. It is a great way to reuse and make money in the process.
Lunch Box Conservation: Use your lunch box as a test case. List those items in your lunch box on a typical day. Place all the items under categories of Reduction, Reuse, Recycle, and Landfill. Redesign your lunch containers to allow you to reuse everything.
Extensions:
Research Study: Ask students to design and conduct a research study related to solid waste management. Select a local solid waste issue to
investigate either individually or as part of a small group. Develop a research question. Decide if you will need to collect any data and how this will be done, i.e. surveys, questionnaires, or inventories. Prepare a summary report to be presented to the class. Be sure to include your research question, methods,
and findings. Students could work in small groups, but you may want to brainstorm ideas as a class. Here is a possibility: Ask your local grocery store if you can conduct a study in their store to determine the effects of "information" on item sales. Prepare a sign that encourages consumers to "shop
green" by buying cardboard cups rather than Styrofoam. Place the sign on the cup display in the store. Compare sales of cardboard and Styrofoam cups with and without the sign.
Action Plan: Investigate one area of solid waste in your community, school or home. Design a plan to do something to decrease one aspect of solid waste. Some suggestions include, 1.) Contact a local hair styling salon. Salons use a large quantity of plastic containers for hair treatment. Develop a plan for helping this establishment set up a plastic recycling bin. Show them how easy it is to collect and periodically take their plastic to a local recycling center. 2.) Check your local stores to see if they sell Styrofoam cups and picnic plates. Try to encourage them to discontinue carrying these plastic items and replace them with paper products. You may have to collect some data from consumers related to their preferences in order to convince store owners to change. 3.) Write a column for your school newspaper which encourages recycling and place posters around school to encourage recycling, etc. 4.) develop a "tip sheet" for home recycling. Have the tips placed in the local newspaper.
Teacher Notes
Objective:
In this activity, students will observe the fibers making up paper. They will attempt to discover a relationship between the thickness and strength of paper
and the fibers from which the paper is made. Students will also design a method for testing paper strength.
Materials:
paper samples (tissue, onion skin, typing, brown paper bag, cardboard, cardstock, paper towels, toilet paper, recycled paper, etc.; binocular microscopes or hand lenses; baby food jars and water
Background:
Paper is made of layers of fibers. The fibers are tangled and lie on top of one another. Papermaking fibers are cellulose, which comes from plants. Cellulose
fibers make the roots, leaves, and stems of plants strong and rigid. When paper is made, millions of fibers are placed together in a thin layer. The length and number of fibers contribute to the strength and texture of the paper. Why don't all the fibers fall apart when you blow your nose on a tissue? The fibers have
a built-in hold on one another. Water deactivates this hold. When paper gets wet, it is much easier to tear the fibers apart. But when dry, the fibers hang
onto one another very strongly. Every piece of paper is a source of fibers. The fibers making up some types of paper are more easily loosened than others. If the fibers can be loosened with water and tearing, they can be rearranged
into new paper. Water loosens the bond and removing the water strengthens the bond between fibers. In the past, papermakers have gotten fibers for paper from just about everything that grows. Some plants that have been used to make paper include asparagus, bamboo, cabbage stumps, corn husks, lily of the valley, moss
and seaweed. Hornet's nests were also used to make paper. Today, papermakers get most of their fibers from trees.
Suggested Teaching Strategies:
In the next activity, students will be making their own recycled paper. Before they do that, however, it is a good idea to take a closer look at paper. By
comparing different types of paper, students will hypothesize about the relationship between fiber number, length and thickness and the strength of paper. Students will then design their own method for testing the strength and
quality of paper. Students will be able to use both the strength test and the quality rating scale in experiments with their homemade paper (Activity 3).
Begin by asking students to look at the fibers of different types of paper under a binocular microscope (or using a hand lens). The fibers can best be seen by tearing a piece of paper and observing the paper along the tear. Students should compare as many different types of paper as possible. In order to compare the fibers from different types of paper, students need to record observations of the paper. Challenge students to develop some way to describe their observations that will allow them to compare the relative number and length of fibers.
Another way to get a closer look at the fibers making up paper is to suspend the fibers in water. Ask students to choose three types of paper which they believe have quite different fibers. Place torn-up pieces of each type of paper into three separate baby food jars that are about half filled with water. Place the lid on tightly and shake each jar vigorously. Using a hand lens, look closely at the water in each jar. The fibers will be floating in the water. Ask students to experiment with the paper to determine answers to as many of the questions below as possible. Remind students to control as many variables as possible. Place a copy of these questions on the overhead or chalkboard. (See Appendix A. If you are using the attached student worksheet this will not be necessary.
Questions to Investigate
Sample Answers to Summing Up:
1. Student's rating sheets should include a variety of characteristics and should contain either verbal descriptions of numerical ratings for the different characteristics. The rating sheets will likely vary greatly from student group
to student group. This is O.K., as there is no one answer to this question. Check to make certain that students have used their rating sheets to rate several samples of paper.
2. Student's methods of testing paper strength will also vary. Make certain that their explanation of how the strength test is carried out is clear and concise. Students should test several paper samples using their specially designed strength test.
Home/Community Connection:
There are many purposes for paper. Conduct a home paper survey. Prepare a list of as many different uses for paper as you can discover around your home.
Extensions:
Develop a product rating system for paper durability, both wet and dry. Test your paper samples, giving them a durability rating.
Student Page
Problem:
Find out if there is a relationship between the thickness and strength of paper and the fibers from which the paper is made. Also, design a method for testing paper strength.
Materials:
paper samples (tissue, onion skin, typing, brown paper bag, cardboard, cardstock, paper towels, toilet paper, recycled paper, etc.; binocular microscopes or hand lenses; baby food jars and water
Let's Investigate:
Taking a Look at Dry Fibers...Using a hand lens or binocular microscope, take a look at the fibers of different types of paper. The fibers can best be
seen by tearing a piece of paper and observing the paper along the tear. Compare as many different types of paper as possible. Record your observations by developing some way to describe your observations that will allow you to compare the relative number and length of fibers.
Taking a Look at Wet Fibers...Another way to get a closer look at the fibers making up paper is to suspend the fibers in water. Choose three types of paper which you believe have quite different fibers. Place torn-up pieces of each type of paper into three separate baby food jars that are about half filled with water. Place the lids on tightly and shake each jar vigorously. Using a hand lens, look closely at the water in each jar. The fibers will be floating in the water. Experiment with the paper to determine answers to as many of the questions below as possible. Remember to control as many variables as possible. Place a copy of these questions on the overhead or chalkboard.
Questions to Investigate
Summing Up:
1. Design a scale for rating the quality of paper. Include strength, texture, durability, write-ability and anything else that would be an important
characteristic of paper. Be sure to include an explanation of each quality listed on your rating sheet. Use your rating scale to rate each of the paper sample available.
2. Develop a way, or an apparatus, for testing paper strength. Write an explanation of how your strength test is carried out. Try the test on each of the paper samples. Write a summary of your strength test results.
Teacher Notes
Objectives:
Students will design their own experiments to create and test various types of recycled paper.
Materials:
newspaper (a big stack)
buckets or tubs (one per student group)
wire screens: one per student group (approximately 20 cm square)
blenders (an egg beater or medium jars with tight lids may be used in place of a blender)
rolling pins (several for the classroom)
lunch trays or flat pans (one per student group)
paper towels for clean-up
strainers (to strain pulp from waste water - several for the classroom)
cornstarch (optional)
food coloring (optional)
pieces of thread, flower petals, & other thin, but decorative items (optional)
food coloring (optional)
Safety Warning:
Using a blender or even an egg beater can be dangerous. Students must be
reminded to keep hands and long hair well away from the mixers. The blender should be unplugged at all times when not in use.
Background:
Every piece of paper is made up of fibers. Separate them and you can use them
to make new paper. They are as good as new fibers for most purposes, and better for some. For no money at all, you can get all the fibers you want. Used paper is called wastepaper. But don't let the word "waste" fool you. Some paper
sacks and greeting cards contain the finest fibers available. By recycling, these fibers can be used to make new paper from old. Recycling paper works because water weakens the bonds between fibers, allowing them to separate.
When students recycle most kinds of paper in this activity, they will likely make gray paper. Recycling paper with print or pictures on it makes gray paper. For white paper, recycle only paper with no printing or writing on it. Cut out the unprinted parts from envelopes and cards and the margins of newspapers and magazine pages to produce white paper.
Paper companies make strong paper from long and/or well-beaten fibers. These long fibers can be found in grocery sacks, wrapping paper, and good writing paper. It is usually necessary to mix the fibers more thoroughly when attempting to disconnect the fibers in the paper. Strong paper cannot be made from tissues, newspapers, comic books, or paperback books. Some greeting cards make weak recycled paper. Experimenting with different fibers will show which materials make the best recycled paper.
Recycling materials to make paper dates back to the time when paper was made from old linen clothing. When this supply became inadequate to meet the demand for paper, the paper manufacturers turned to trees. It takes a great deal of energy to harvest the trees, shred them, and separate the fibers from the lignin which holds the fibers together. Waste chemicals are also produced. Getting rid of these chemicals could mean heavy pollution of streams and rivers. Water purification associated with paper making is an expensive, energy-consuming process.
Suggested Teaching Strategies:
This activity may be carried out in the classroom or outdoors. In either case,
advanced preparation is very important. The materials needed are somewhat dependent on where you choose to carry out the activity. In either case, be prepared to have a spot reserved where students can leave their paper, at least
overnight, to dry. This should be a flat area that won't be damaged by damp newspapers.
Before students begin the activity, review the procedure for making paper, including safety, and the clean-up process. Demonstrate alternative methods of making the pulp....using a blender, an egg beater, and a sealed jar containing water. The procedure is outlined on the student page, however, you may choose not to use this sheet, providing verbal directions instead. Whichever approach you choose, demonstrating the technique is advised and should minimize potential clean-up problems.
Begin the activity by demonstrating the pulp making process using the shaking method. Tear small strips of newspaper and place them in a glass jar with some water. Seal the jar and shake. (Have one ready that has already been shaken to produce pulp!) Place the screen over the open jar and invert it, allowing the excess water to drip into a waste bucket while the pulp remains in the jar. Now dump the pulp onto the screen and spread it around with your hand. If it doesn't cover the screen, you have not made enough pulp. Simply make more and add it to the screen. Once the screen is covered evenly, set it on a lunch tray or in a flat pan. Place a page of newspaper over the screen and roll the paper. This helps flatten the paper and removes the excess water. If you prop up the tray a bit, the water will drain away from the paper sample. Place the excess water in the waste bucket. The recycled paper can now be peeled off the screen, placed on a dry sheet of newsprint and allowed to dry overnight.
The paper making will progress quickly if you have one screen for each group. As the paper is removed from the screen, it will be possible for each student in the group to make several pieces of paper during one class period. While one member of the group is rolling his/her paper, other members can be tearing paper and shaking it is the jar or using one the classroom blenders. It is nonproductive to have students stand in line waiting for use of the blender. Having three different methods of making pulp (blender, shaking, and egg beater) helps to minimize the waiting process.
This activity has the potential of being quite messy. The ideal place to carry out the activity is on the school playground. If you will be doing the activity outdoors, you will need to have a source of water. Carry out several (3-4) buckets of water, along with the other supplies. Be sure to go over the directions while still in the classroom.
Tips for Making Good paper:
You may speed up the drying process by covering the paper sample with a towel
and ironing. Make certain the paper is laying flat while drying. If not, it will dry curled up and will be difficult to write on.
Clean-up Tips:
Have several waste buckets available for students and show them what they are for. Each time students dump off excess water or smooth the recycled paper with the rolling pin,. excess water comes out. This water should be placed in the
waste bucket. When it is full, simply dump it through a strainer. The strained water can be dumped down the drain, while the pulp waste should be placed in the garbage. Stress that students are not to throw the pulp mixture down the drain, as it will gum up the sink. The strained pulp can be stored in plastic bags in
your freezer until next time you need it or thrown in the garbage.
Student's hands will be very dirty with newsprint ink. Allow time for students to thoroughly wash their hands with soapy water at the end of the activity.
Because this technique is so simple, students can easily experiment with many different combinations of recipes, while getting quick results. The student page contains a number of suggestions for experiments in making recycled paper. Go over these ideas with the class before they begin working on their paper.
Research Question
Sample Answers to Summing Up:
Student answers to both summing up questions will vary. Make certain that students take the time to record their procedures and findings for both
questions. Students would find it interesting to carry out a final portion of the strength test as a class, using the strongest paper from each group. This would also be a good time to share each groups "favorite" paper sample with the
class, along with any "secret" recipes they may have developed.
Home/Community Connections:
Start a family paper making project by showing your relatives and siblings how to make paper. Have each family member design and make their own paper.
Look around your home and locate as many different examples of products made from recycled paper as you can. In most cases you will need to read labels to determine whether a product is made from recycled paper.
On what types of packages in your home can you find the words "post-consumer waste" and what do they mean?
Extensions:
Discover whether the paper wasp is really able to make paper. Describe how it is done and how it relates to the methods humans use to make paper.
Conduct some research on paper making. Use references to find new recipes for making paper. Try some of these at home.
Student Page
Problem:
Experiment with and refine a recipe for making recycled paper, then judge the quality of the recycled paper.
Materials:
bucket or tub, newspapers, wire screen, mixer, rolling pin, corn starch, food coloring, interesting paper scraps and other colorful items.
SAFETY WARNINGS:
If you will be using a blender or egg beater to break down your paper fibers, keep all hands and long hair away from the apparatus. Always unplug the mixer when you are not using it.
Let's Investigate:
Cut or tear a newspaper page into small pieces and soak them in water. Pour off the excess water and place the pieces in a blender. (If you don't have a
blender, you may use an egg beater or can seal the torn paper in a jar containing a small amount of water, then shake it vigorously.) Sprinkle about 1 tablespoon of starch in the water and blend at high speed until it looks like
thick soup. Pour the mixture onto a piece of wire screen, spreading it evenly with your fingers. To remove the excess liquid and to get the paper flat and thin, roll the rolling pin over the mixture while it is on the screen. Peel off the wet paper and carefully place it onto a dry page of newspaper. Allow it to
dry overnight.
Research Question
Summing Up:
1. Use the rating sheet developed in Activity 1 to rate the different kinds of recycled paper made by your group.
2. Use one of the strength test designed in the last activity and test the different kinds of recycled paper made by your group. How was the strongest paper made?
Teacher Notes
Objectives:
Design experiments to discover the biodegradable nature of some packing materials.
Materials:
Styrofoam packing peanuts
starch packing peanuts
acetone (optional)
water
stirring sticks (popsicle sticks)
beakers or baby food jars
safety goggles
Background:
In the 1850's, Alexander Parkes, an English chemist, made the first plastic material. Today, plastics are made from the chemicals in oil. They are used to make toys and many household products such as containers, Styrofoam, etc.
Because Styrofoam is made from oil, the production of Styrofoam depletes one of our nonrenewable resources. It takes billions of years for oil to form. It also adds more garbage to our world because Styrofoam is permanent garbage. It will not break down in a landfill. Most of the Styrofoam we produce will still lie buried in the landfill five hundred years from now.
One of the largest uses of Styrofoam today is for packing material. It is ideal for this purpose because it provides a nice, soft cushion for breakable materials. It is also very light, so it doesn't add much to the cost of sending materials by mail. If you receive a box in the mail that was not quite the right size for the materials it contains, it will likely be filled to the top with packing peanuts. Several years ago, these packing peanuts were made of Styrofoam. Today, a better alternative has come on the market. . . packing peanuts made from entirely natural materials. These peanuts are degradable and dissolve in water.
What allows these peanuts to dissolve in water? Water is a solvent for the peanuts. Solvents are chemically compatible solutions of similar molecular composition that allow a material to dissolve in it. Cornstarch dissolves in water and degradable packing peanuts are made from cornstarch. Styrofoam peanuts dissolve in acetone (fingernail polish remover). The acetone solvates the polystyrene resulting in the collapse of the structure and the release of the gas that contributed to the colloid. This means the acetone dissolves. The polystyrene is made of lots of long molecules hooked together. When the acetone touches these hooks, they fall off and the molecules fall together in a heap, squishing out the air as they fall. All that is left is the plastic (polystyrene) without the air. The same thing happens with the cornstarch. The water yanks the hooks off, allowing the cornstarch to fall apart. Because cornstarch packing peanuts dissolve in water and produce harmless materials, they are considered to be environmentally friendly. They are even considered an acceptable soil enhancer.
SAFETY WARNING:
If you are having students do the acetone portion of this experiment, insist that they wear safety goggles. Acetone is a flammable liquid. Keep it away
from heat, sparks, or flames. It is harmful if swallowed. If inhaled, remove to fresh air. If swallowed, induce vomiting immediately by giving two glasses of water and sticking a finger down the throat. Call a physician immediately.
For eye contact, flush with water for fifteen minutes an get medical attention immediately. If skin contact occurs, wash skin with soap and water.
Suggested Teaching Strategies:
It is important to have a variety of types of packing peanuts available for this activity. Start saving peanuts well in advance of this activity. Spread the
word throughout your school that you are looking for peanuts, asking other teachers to save them for you. You need an adequate number of both Styrofoam and cornstarch packing peanuts.
How do you know which kind you've got? There are a number of starch-based packing peanuts, with a variety of brand names. Some include "Eco-Foam" and "CLEAN GREEN". They may be white and cylindrical or tubelike and cream colored. Rather than going by appearance, it is better to simply test a sample of each type of peanut. To discover which are which, simply place a sample of each type you locate into a cup of water. If the peanut dissolves, it is a starch-based nut. If it doesn't, it is made from polystyrene (Styrofoam).
Provide students with some background information on Styrofoam. Many students will not realize that Styrofoam is made from oil. They may not be familiar with the term degradable. Styrofoam is bad for our environment not only because it is made from oil, a nonrenewable resource, but because it does not break down in the landfill...it is not degradable. Students will be designing and carrying out experiments to answers the questions shown in the box on the student page.
Once students have separated their peanuts into two piles (Styrofoam and cornstarch), set up a class demonstration to test their Styrofoam samples in acetone. Ask students to hypothesize as to what they think will happen to the cornstarch peanuts when they are added to a different type of liquid, acetone. Tell students that acetone is the main ingredient in fingernail polish remover. Try it on some of the student samples. (The cornstarch peanuts will not dissolve in the acetone.)
Now add polystyrene peanuts to the acetone solution. Stir the concoction with a wood splint or popsicle stick. How many nuts can be added before they stop dissolving? Pull the polystyrene blob out of the acetone and rinse it with water. Experiment with the poly-blob. Ask students to make a list of the properties of the poly-blob. How do they compare to the cornstarch peanut blob?
Sample Answers to Let's Investigate Questions:
1. Students should discover which are degradable and which are not by placing samples of each type of packing peanut into water. if the peanut dissolves, it is degradable. If it does not dissolve, it must be made of Styrofoam.
2. As the peanuts dissolve, they form a bubbly mass of goo. The more peanuts that dissolve, the thicker the water-peanut solution becomes. Some carbon dioxide should be released as the peanuts dissolve. Students should note the appearance of bubbles.
3. The number of peanuts that will dissolve in water is dependent on the amount of water and the type of peanut. If students are comparing two or more types of degradable peanuts, they should set up some controls in their experiment. These might include keeping the amount of water constant and massing the peanuts rather than counting them. This would control for the varying sizes of the peanuts.
4. It is safe to hold the blob, although it will be very gooey. The more peanuts added to the water, the easier the resulting blob will be to handle. Students should experiment with stretching, bouncing, and feeling the blob.
Sample Answers to Summing Up:
1. The advantage of replacing all Styrofoam packing materials with
cornstarch-based materials would be that the cornstarch. The cornstarch peanut will dissolve in the water but not in the acetone. The polystyrene peanut will dissolve in the acetone but not in the water. As you add more peanuts to each
cup you eventually end up with a glob of plastic and some slimy cornstarch. A small amount of carbon dioxide that has been trapped in the foam will also be formed.
2. It would not be wise to use cornstarch-based materials in cups and plates because anything containing water that is placed on or in these containers would cause it to fall apart.
Home/Community Connection:
Locate a variety of Styrofoam materials around your home. Test them to
determine whether they are made from cornstarch. List your findings in a table. Explain which of these uses for Styrofoam could be replaced with the cornstarch packing material?
Extensions:
Making Slime . . . Some starch packing peanuts (i.e., Eco-Foam) contain a synthetic additive called polyvinyl alcohol, which makes them more flexible and
resilient. Both Styrofoam and starch peanuts can contain PVA. It is possible to cross-link the chains in these molecules to create "slime". Peanuts that do not contain PVA will not make slime.
If you have peanuts containing polyvinyl alcohol (PVA), it is possible to form slime from them. Students can experiment with a variety of packing peanuts to find out which ones contain PVA. After dissolving a handful of peanuts in
water, students add sodium borate solution to make slime. If PVA is present, the chains will cross-link and the mass will become very thick and hard to stir. Students can knead the slime by hand, then observe its physical properties. (You can also make slime from Styrofoam peanuts, but the peanuts must first be
dissolved in acetone.) Disposal of slime is easy, just throw it in the trash. It is not a good idea to allow students to take the blobs out the classroom, as it can make a real mess around school and home. In order to make the slime you will need the following:
* degradable packing peanuts containing PVA (test yours to see)
* food coloring (optional)
* 4% sodium borate solution (4 grams sodium borate in 96 mL of water)
* eye droppers
Pour about 20 mL of tap water into a beaker or jar. Add a handful of starch-based packing peanuts of one variety. Using an eye dropper, add about 2 mL of sodium borate solution and stir. A drop of food coloring may be added to color the "slime". If the peanuts contain PVA, the mass will become very thick and hard to stir. If the mixture does not thicken, the peanuts do not contain PVA. Begin again with a new variety of peanuts if slime does not form. If the mass is too runny, add another 2 mL of Borax solution. Once the slime is thick, pull it out and knead it by hand. Make observations about the slime's physical properties.
Student Page
Problem:
Discover which types of packing materials are degradable.
Materials:
packing peanuts
water
beaker or baby food jar
stirring sticks
SAFETY WARNING:
Do not eat any of the dissolved peanuts.
Let's Investigate:
Some types of packing peanuts are better for our environment than others. Peanuts made from cornstarch are degradable. They fall apart when water is
added to them. Your job is to determine which packing peanuts are made from cornstarch and which are made from Styrofoam. Using the materials your teacher has provided, set up your own experiment to determine which packing peanuts are
degradable and which are not. At the end of your experiment, you should have all your sample peanuts in two piles: ones made from Styrofoam and ones made from cornstarch.
Conduct experiments that will allow you to answer as many of these questions as you can. Be sure to write your answers in an organized fashion.
Experiment and Answer These Questions
1. Which packing peanuts are degradable and which are not?
2. Observe what happens to the peanuts as they dissolve. Describe all of these changes.
3. How many peanuts can you get to dissolve in the water?
4. Make a list of the properties of the resulting blob. (It is safe to pull it out and hold it.)
Summing Up:
1.What would be the advantages of replacing all Styrofoam packing peanuts with corn-starch based peanuts?
2. Would it be practical to replace all the Styrofoam used for Styrofoam cups and picnic plates with the cornstarch material used in some packing peanuts? Why or why not?
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